GitLab

Adds a function to SpeechMonitor to block until a stop
event is called. This will be used in later tests.

Bug: 789598
Change-Id: Id25069e60d472eed3bf363e9cf597d2fe07d91e2
Reviewed-on: https://chromium-review.googlesource.com/804415
Commit-Queue: Katie D <katie@chromium.org>
Reviewed-by: Dominic Mazzoni <dmazzoni@chromium.org>
Cr-Commit-Position: refs/heads/master@{#521379}